Sometimes crashes gnome-shell in Gnome 3.26

Created by: toupeira

Sometimes starting/stopping an activity using the CLI start / stop commands (while having the shell extension loaded) causes gnome-shell to crash with this error:

Nov 01 13:01:22 ocelot gnome-shell[21543]: JS ERROR: TypeError: layout is null
                                           HamsterExtension.prototype._refresh@/home/mak/.local/share/gnome-shell/extensions/hamster@projecthamster.wordpress.com/extension.js:375:13
                                           _proxyInvoker/asyncCallback@resource:///org/gnome/gjs/modules/overrides/Gio.js:90:13

This happened after I upgraded to Gnome 3.26 so I assume it's related to that. Not sure if it's normal that an uncaught JS error crashes gnome-shell though :) I also don't really know anything about how extensions work, but since it doesn't happen consistently I assume it's some kind of timing issue.